Floating roof storage tanks are a critical component of crude oil, gasoline, and volatile substance storage at refineries, tank farms, and crude oil terminals. While these tanks offer significant advantages in reducing vapor loss and preventing explosive conditions, they also present unique vulnerabilities to lightning strikes.

In this article, we cover these risks, their potential impacts, and identify effective mitigation strategies is essential for ensuring operational safety and reliability.

The Fire Triangle – The Nature of Combustion

The first step to mitigating lightning risk in floating roof storage tanks holding crude oil, gasoline, diesel, and other volatile substances is to understand the process of combustion. The “Fire Triangle” is a simple model for understanding the components of combustion, which can cause uncontrolled explosions and fire.

The three elements of the Fire Triangle include:

1. Fuel. Any material that can be converted into heat energy through combustion. In the case of storage tanks, the obvious fuel is the volatile substance being stored (e.g., crude oil, gasoline, etc.).
2. Heat. An ignition source is required to initiate combustion. The source of the heat may be a spark from a welding torch, hot embers from a fire, or a lightning strike.
3. Oxygen. Oxygen must be present to create a chemical reaction with the fuel, otherwise ignition will not occur.

If any one of these elements is missing, then fire and explosion are not possible. Our focus in this article is on mitigating the potential for lightning to provide Heat element and break the Fire Triangle to avoid combustion.

Risks of Lightning Strikes on Floating Roof Storage Tanks

Lightning is a formidable natural hazard that poses multiple risks to floating roof storage tanks. A lightning strike can introduce the heat necessary to ignite a fire and/or cause an explosion. Common risk factors include:

• Direct Strikes: A direct lightning strike can deliver an immense energy surge, igniting vapors and potentially leading to ignition and catastrophic explosions.
• Secondary Effects: Even if a tank itself is not directly struck, nearby strikes can induce electrical surges and arcs, which can ignite flammable vapors.
• Bonding and Grounding Failures: If bonding and grounding systems are inadequate or compromised, differences in electrical potential can cause dangerous sparking between the floating roof and the tank shell.
• Seal Failures: The seals between the floating roof and the tank wall are crucial for preventing vapor release. Poorly fit or worn seals can allow a substantial amount of oxygen into the tank or permit volatile vapors to accumulate in proximity to the tank. A lightning-induced spark can occur if these seals become damaged or deteriorate over time.
• Internal Vapor Ignition: Although floating roof tanks are inherently designed to minimize the risk of vapor accumulation, vapors can still accumulate in gaps, vents, or around damaged seals can ignite from even a minor spark, leading to fires or explosions.

Potential Impacts of Lightning Strikes

A lightning strike on, or in proximity to, a floating roof storage tank can have severe consequences, including:

• Fire and Explosion: Ignition of flammable substances can lead to uncontrolled fires, tank destruction, and even chain reactions affecting nearby storage tanks.
• Personnel Safety Hazards: Explosions or fires pose a direct threat to workers in the vicinity, potentially causing severe injuries or fatalities.
• Business Interruption: Damage to storage tanks can lead to significant operational downtime, disrupting supply chains and leading to financial losses and/or competitive disadvantages.
• Environmental Contamination: Spilled or burned hydrocarbons can result in soil and water contamination, triggering regulatory penalties and costly cleanup operations.
• Regulatory and Legal Consequences: Organizations and facilities that fail to mitigate lightning risks may face hefty fines, lawsuits, and reputational damage.

Mitigation Strategies for Protecting Floating Roof Storage Tanks

To minimize the risk of lightning-induced incidents, the following best practices and mitigation technologies should be implemented:

1. Charge Transfer Systems (CTS) and Dissipation Array Systems (DAS): These advanced lightning protection solutions, such as the Dissipation Array System (DAS) from Lightning Eliminators & Consultants (LEC), prevent direct strikes by dissipating the buildup of electrical charge before lightning can form.
2. Bonding and Retractable Grounding Systems (RGA): Proper bonding between the floating roof and the tank shell is essential to equalize electrical potential and prevent sparks. Flexible shunts or bypass conductors should be installed and regularly maintained.
3. Vapor Seal Enhancements: Ensuring high-quality, well-maintained primary and secondary seals reduces vapor leakage, minimizing ignition risks.
4. Lightning Protection Systems (LPS): Installing air terminals and grounding systems in compliance with standards such as NFPA 780 can help direct lightning energy safely into the ground.
5. Surge Protection Devices (SPD): Electrical surge protection for connected instrumentation and control systems can prevent damage and reduce secondary ignition risks.
6. Preventative Maintenance and Inspections: Routine inspections of bonding straps, seal integrity, and grounding connections ensure that protective measures remain effective over time.
7. Real-Time Lightning Monitoring: Implementing lightning detection and warning systems allows facilities to take preemptive safety measures before storms impact operations.

The Lightning Eliminators Advantage

Our patented and innovative products are designed to protect fixed and floating roof storage tanks from the devastating effects of lightning strikes, ensuring the safety and integrity of your storage facilities.

Our advanced lightning protection systems are engineered to mitigate risks and keep your operation running through the storm.

Lightning Protection for Storage Tanks (Floating Roof)

Since 1971, Lightning Eliminators and Consultants (LEC) has been protecting critical operations, facilities, and infrastructure from lightning-related risks. Our two primary solutions for protecting floating roof storage tanks include:

Retractable Grounding Assembly® (RGA®750) Generation 2. The award-winning lightning protection design of the Retractable Grounding Assembly (RGA) from Lightning Eliminators reduces the risk of lightning damage and fire by creating a low-impedance bond between the roof and shell. The lightning protection design of the RGA 750 is cost effective, easy to install, and virtually maintenance free. LEC has over 17,000 RGA’s in service worldwide.

READ MORE: RGA Product Page

Dissipation Array® System (DAS®). Our patented Dissipation Array System (DAS) prevents direct lightning strikes by reducing the electric field to below lightning-collection levels, within the protected area. As a result, DAS lightning protection systems help to prevent downtime and loss of assets, while increasing lightning safety for personnel.

READ MORE: DAS Product Page

Conclusion

Lightning strikes on floating roof storage tanks pose serious risks to safety, operations, and the environment. However, by deploying comprehensive lightning protection solutions—such as the Retractable Grounding Assembly (RGA 750) in combination with our patented Dissipation Array System (DAS), you can significantly reduce the likelihood of incidents. Investing in effective lightning mitigation not only enhances safety but also ensures business continuity and regulatory compliance, protecting both assets and lives in the process.

Contact us today to learn how Lightning Eliminators can help you break the Fire Triangle and protect your floating roof storage tanks from lightning-related risks.